1. Field of the Invention
This invention relates to roaming mobile nodes in a visited domain, and more specifically to delegating security procedures, such as authentication and key distribution, to the visited domain.
2. Discussion of the Related Art
Mobile devices such as cellular phones, Personal Digital Assistants (PDA), laptop computers, etc. are abundant in today's society. A large number of people carry mobile phones daily as they travel from home to work and to other places during their day. In most cases, the mobile device has a subscription with a home domain. This home domain keeps information about the user such as the long term key for security procedures but also information regarding the services the user has subscribed and is therefore authorized to have access to, etc.
When a mobile device/node roams to a foreign domain (i.e., visited domain), the user of the mobile node needs to be authorized by the foreign domain to gain access to local resources of the visited domain. The authorization generally consists of the user offering his/her credentials to a local agent (e.g., a local Authentication Authorization and Accounting (AAA) client) in order to verify that the user is authorized (e.g., by roaming agreement between the home domain and visited domain (e.g., Internet Service Providers (ISPs))) and to authenticate the user.
In addition, when a user/mobile node is roaming, many security associations (SAs) usually need to be set up between the user and agents or entities of the visited domain. For example, a security association may be needed between the user and the access router in a visited domain to protect data (confidentiality and integrity protection) over the access link. As another example, in the context of Mobile Internet Protocol (MIP), an SA may be needed between the mobile node (MN) and the home agent when this one is assigned in the visited domain. As a third example, a security association may also be required between the mobile node and mobility agents when a Localized Mobility Management solution is deployed. These security associations typically have a restricted lifetime, and when expired, they need to be refreshed. In addition, in order to avoid fraud, service providers need the ability to force a user to provide authentication information anytime during a session. Both the home domain service provider and the visited domain service provider need to have this capability.
Moreover, to achieve better overall security, a mobile node may want to challenge the network at any time, for example to avoid network impersonation attacks, man in the middle attacks, etc. All these procedures require the involvement of the home AAA server (AAAh), since only the user/mobile node and its home domain share a long-term key. This implies that several message round trips are needed between a visited domain and a home domain in order to support the above-mentioned authorization/authentication and key distribution procedures. These message exchanges between the home domain network and visited domain network may create an excessive signaling load between the AAAh and visited AAA server (AAAv,) and also may add delay in the procedure.
Therefore, a need exists for method and apparatus that allows a user/mobile node and a visited network to perform authentication and key distribution procedures without requiring many round trip communications between the visited network and the home domain network of the user, and that provides a local security association (LSA) that allows for optimizations and empowers a visited network to authenticate a user at any time, as well as empowers the user to authenticate the network at any time, and performs key distribution procedures without the involvement of the home domain, while still maintaining a good level of security.